The Center for Clinical Epidemiology and Biostatistics (CCEB) and the Abramson Cancer Center (ACC), an NCI-designated Comprehensive Cancer Center, in collaboration with the Division of Hematology-Oncology of the Department of Medicine and the Division of Oncology of the Department of Pediatrics, all of the University of Pennsylvania (Penn) School of Medicine, propose to continue an innovative, rigorous, and successful two- to three-year training program for clinical investigators in cancer clinical epidemiology. This training program attracts cancer clinical epidemiology trainees from institutions nationwide; its graduates are placed in institutions nationwide, resulting in a program of high impact. The training program consists of required courses in clinical epidemiology, research methodology, biostatistics, and cancer clinical epidemiology; elective courses relevant to the trainees' methodologic interests; journal clubs and clinical research conferences conducted by participating faculty, the CCEB, ACC, and adult and pediatric oncology divisions; extensive independent readings; instruction in the responsible conduct of research; an apprenticeship-type experience with an experienced investigator (recommended); and the completion of an independent publishable research project in cancer clinical epidemiology. The program will: 1) train physicians to be rigorous and independent academic investigators able to use the range of approaches available in epidemiology to address research issues in cancer related to the etiology, prognosis, prevention and early detection, treatment, clinical economics, technology assessment, medical decision making, and quality of patient care; 2) provide closely mentored research experiences with faculty preceptors in clinical epidemiology and cancer; and 3) strengthen the links between traditional epidemiology and cancer. Trainees will matriculate in the Master of Science in Clinical Epidemiology (MSCE) program. Strengths of the proposed program are: 1) the long history of successful research training programs in the CCEB, ACC, and adult and pediatric oncology divisions, including this training program; 2) the collaborative links that have been forged among faculty with interests in clinical research in cancer; 3) the comprehensive course offerings and research programs that are available to trainees; and 4) an extensive set of experienced and multidisciplinary faculty with successful training records. In addition, numerous existing large databases that can be used for research projects and training; a broad array of specialized analytic capabilities available for clinical studies employing methods of clinical epidemiology (e.g., clinical trials, case-control, cohort research, etc.); and commitment of faculty to collaborative research and training, combine to provide an ideal environment for this training program. Finally, Penn and the School of Medicine promote an academic environment in which basic and clinical research are encouraged and viewed as attractive career paths for physicians.